Electrical switch.



Nl. H. JOHNSON.

ELECTRICAL SWITCH.

APPLICATION HLED vec ze. 1911. nENEwED Nov. 3. 1914.

1,174,162. Patented 113,117,191@

3 SHEETS-SHEET 1.

AMPEAES A WITNESSES:

25 "f WMV/*5M ATTORNEYS THE COLUMBIA PLANOGRAPH C0.. WASHINGTON. D- C- II/I. II. IOHNSON. I

ELECTRICAL SWITCH.

APPLICATION FILED DEC. 26, IaII. IIENYEWED Nov. 3. I9I4.

1,174,162. y' PaIenIedI/Iar. 7,1916; 3 SHEETS-SHEET 2.\

IIIIll II, /s lll, V-II .33r n Q1 y INVENTOR v V WITNESSES! ATTORNEYS THB COLUMBIA PLANOGRAPH co., WASHINGTON. D. c.

M.H.1OHNS0N.

ELECTRICAL SWITCH.

APPLICATION FILED DEC.26, I9'II. RENEWED NOV. 3, 1914.

Patented Mar. 7, 1916.

s fs ff ATTORNEYS THE COLUMBIA PLANOGRAPH co., WASHINGTON. D. c.

- miran sTn'rEs EATENT oEEioE.

MONTGOMERY H. JOHNSON, E UTIOA, NEW YORK.

ELECTRICAL Y SWITCH.

Application filed December 26, 1911, Serial No. 667,661. Renewed November 3, 1914. Serial No. 870,170.

To all wIlL-0m it may 'concern Be it known that I, MONTGOMERY I-I. JOHNSON, of Utica, in the county of Oneida and State of New Yorlnhave invented certain rnew and useful Improvements in Electrical switches and switch boards. Vhile it is parous places where'more or less similarY prob-` lems are-encountered.`

One object of myinvention is to provide van electrical switch wherein a removable plug serves to *rendery ymechanically operai ltive the connection between the switch` lever and the contact armfsothat movement of the lever when the kplug is not iny place produces nomovement ofthe Contact arm. A further objectV is--touse one plug to moval of said plug, a

Another object isr to so proper movement .of the contact arm may complete the c1rcuits,.but asimilar movement of the contact arm will not completek thel circuits if the plug is not in place. By

reason of this double controly through the plug, I am able to doubly safeguardagainstv accidental velectrical connections. Also I am able to usevk the plugto' make electrical rconf nection for some circuits by'its mere insertion and at the Sametime use lthe plug in;

its usual double way as to other circuits.-

Another ob]ect is to useone plug as anecessary pai-tof one or one series ofcircuits `and as a locking element Vto render operative the switch controllingthose circuits or other1 circuits,l or both.

One ofthe 'objects to'be obtained invention is a switchboard of such construction that different parts ofthe lighting sys- Specification of Letters Patent.

i construct switch board that kwith the plug in place the Patenteaiviar. a, 1916.

tem may be used as desired and the ignition current may be taken from the magneto. or fromthe storage battery, or froml the storage battery and dynamo. rlhe current from the Vstorage battery and dynamo can be indicated by the -voltmeter and ampere vmeter when desired.

It will beunderstood also that the arrangement of the ignition switch and the switchboard is Vsuoli that only one of the ignition circuits can be in operation at one time by reason of the fact that a single contact arm is a necessary part o'f both circuits,

Aso that when it is moved tocomplete one circuit itsis removed'from the other circuit; there is also a neutral position for this contact arm in which position both circuits are broken.y v

Provision is also made yto charge the storage battery and test the same by voltmeter and ampere meter, and to disconnect the dynamo from the storage battery when desired.y i i Another object is to provide a switchboard where the movement of one `lever operates to close the ignition circuit from the magneto, and also to connect the dynamo to the storage battery, whilev a reversal ofthe lever will break the ignition circuit from the magneto and also disconnect the battery from the dynamo. In this way I provide for normally charging the battery during' running of the engine and also prevent the battery from dischargingv through the dynamo whenthe engine is not running. Of course independent' means are provided for breaking the circuit from the dynamo to the battery so'the latter will not be injured nor current wasted byovercharging.`

A further lobject is to'so arrange the switchboard that the Aplug cannot be withdrawn except whenthe ignition and charging switch has been moved to neutral position; and to make the lever of the ignition'and charging switch act as a lock to ioO yprevent the withdrawalof the plug, except,

los

combinations and yyet safeguards against imi proper interference.

The drawings'illustrate my invention as l applied to af'switchboard onthev dashboard of an automobile, the switchboard being in a substantially perpendicular position.l

Figure 1 is a general plan viewof an electrical switchboard embodying my invention, the cover being largely broken away and the different handles being removed, and the two main levers being shown only in dotted lines. Fig. 2 is a perpendicular section view on line 2--2 of Fig. 1. Fig'. 3 is a'horizontal sectional view on line 3-3 of Fig. 1. Fig. -l is a. perpendicular sectional view on line 2-2 of Fig. 1 of the parts adjacent the plug. holes on `an enlarged scale. Fig. 5 is a horizontal sectional View .on line 5 of Fig. 1. Figli is a )erpendicular sectional view on line (S- of Fig. 1. Fig. 7 is a horizontal sectional view on line 7--7 of Fig. 1. Fie's. S and 9 are side and top views respectivey ofthe plug; and Figs. 10 and `11 are cross-secti0nal views'thereof on lines 10--10 and 11-11 respectively of Fig. 8 on an enlarged scale. Fig. 'f12vis` a front plan view of the switch lever ofthe lighting switch. Fig. 13 is a front plan view of the switch lever of the ignition and battery charging switch. Fig. 14 is a front plan view of a modified form of the contact plate. Fig. 15 is a horizontal .sectional view on line 15-15 of Fig. 1.

`rllhe switchboard is housed within a box or fasing of convenient size consisting of top pieces 11 and 12,-bottom 13, removable back 14k and removable front cover 15, and a .perpendicular partition 16, `which is of wood or other insulating material and divides the box into two compartments. In the front compartment is mounted on the partition 1G as a Abasetlie various parts of the switchboard, while the back compartment serves as a convenient chamber for carrying the various wires to the parts of the switchboard to which they are connected for which purpose vit will be understood holes will be made inthe partition or base 16 where desired.

Secured upon the central part of the base 16 is the inner conducting-pivoting plate 17. This plate has round hole 18 therethrough adapted to receive the plug l19, and around the hole is an annular iiange 20 upon which is pivoted the movable contact arm 21 to which a little below the flange 20 is pivoted by pin 22 the lower end of the lighting switch lever 23. The contact arm 21 extends upwardly far enough to be swung into contact with side vlights contact plate 24:, head lights contact plate 25, and vtai'llight contact plate 26, all o'f which are secured to the base 16 in any' convenient manner. The lighting switch lever 23 extends upwardly from its pivoted connection with the contact arm, over the hole 18 in `the conducting plate 17, at which point there is provided a similar round hole'v27 adapted to receive the plug 19 and to be in line with the hole 1S when the lever 23 is in alineinent with contact arm 21, as indicated in dotted linesinFig. 1. The upper end of the lighting lever 23 is provided with a pin 2S which projectsthrough an opening 29 in the front cover 15 and then receives a suitable handle 30. A strap or bridge 31 is mounted on the l conducting plate 17 to keep the lever 23 and contact arm 21 in position, while a round hole 32 in the bridge 31 in line with the hole 1S in the conducting plate 17 admits the plug 19 and holds it against sidemm'ement.

The plug 19 has its `body of conductive metal and with the exception of its upper side, which is iiattened for purposes hereinafter mentioned, the plug is circular in cross-section to afford ample electrical contact surface with the parts through which it extends, and toafl'ord an easy but close fitting pivot for the parts pivoted thereon. Near the point end of the nlug shank an encircling groove 19 a'tforcs mea-ns for engagement by a spring catch 38 located in an opening 1(3fL in the base 16 when the plug has been placed in the switch.

The mechanical operation of the switch thus far described will'be as follows: lVixen the plug 19 is not inplace movement of the lever 23 by its handle 30 will simply move the lever from sideto side `with the pin 22 as its pivoting point, but will be inoperative tovinove the contact arm 21 as the lever 223 and arm 21. though sideby side have only one fastening point common to `both and that is a loose pivoting fastening. It will be understood, ofcourse, that the contact arm 21 has suliicient friction. against the contact plates 24.-., and 2G to prevent the friction of the adjacent lever 2? from moving the contact arm 21.

It will be obvious thereforethat unless the plug 19 is in place, movement ofthe lever will be inoperative to move the contact arm 21 from its 'former position. lVhen the plug is inserted inthe switch it will be seen that the plug will act as a Eloclcholding the lever 23 and contact arm 21 `in line at another or second point, and so 4locking the contact arm to the leverand causingthem to swing together around 'the plug 19 as a pivot and thereby causing 'the upper end of the contact arm 21 'to move in the same direction and to the extent that fthe lever 28 is moved. i

As far as the switch now described is concerned, the plug 19 can be removed when the lever 23 and contact arm 21 are in any position and can be inserted again when those parts are in any position in alinement with each other. If the lever has been moved since the removal of the plug, the parts can be brought into alinement by pushing inthe plug as far as it will go, that is, until it strikes the lever 23 Vand then moving the handle lback and forth until the hole 27 is found by gentle pressure upon the plug; but this trial proceeding will rarely f be necessary as the operator willi usually remember the position of the switch and under normal circumstances the position ofthe switch will beindicated 'by the lights.

- Secured to the base 16 to the right of the conducting plate 17 is thev stationary conv` ducting pivoting plate 34;. Thisplate, ex-

l tends to the left over the plug holes of the o 37 in the conducting plate 34 is an annular flange 39 about which is pivoted the swinging contact arm 40 of this switch, between which and the bridge 36 secured to platey 34 is the lever 41 for this switch having plug hole 42 therein.' A little distance down from the plug holes the lever 41 and contact arm 40 are loosely pivoted to each other by pin 43. The lever 41 extends downwardly through slot 13b to a point without the switch box where it receivesa handle 44. Below pivoting pin 43 the Contact arm is bent toward the base 16 and then extends downwardly parallel thereto in order to make contact with various contact plates secured to the base 16 to either side of a middle position, as will be fully described hereafteii The plug hole 38 in the bridge 36 is not round like all the plug holes in its conducting plate 34', the conducting plate 17 and its bridge 33, but is D-shaped to closely it the upper flattened side 19h of the plug 19.l This arrangement prevents the plug 19 from rotating when in place and in that way lessens the tendencyof the plug to work loose upon' the operation of the different switches. Its

main purpose, however, is to hold lthe'plugv from being rotated and thereby form part of a locking device 'which prevents the plug itself from being withdrawn except when the ignition and charging switch lever 41 is in neutral position. The plug'hole 42 in this lever 41 is also D-shapedto lit the-flattened shank of the plug but at the part of the plug shank that'is encircled by thelever 41 `when the plug is Vin place, there lis p`ro- Vvided an annular groove 19C of such depth that the lever 41 may freely swing'around the plug 19, notwithstanding the D-shaped hole`42 in the lever 41. j As soon, however,

as the leverA 41 'is swungfrom its middle or neutral position the flat side of the hole 42-v will enter the groove 19C of the plug and will, therefore, prevent the removall of the l plug so long asthis ignition and charging switch is in eitherl operativeposition; In `this-way theoperator is obliged toy move the ignition and .charging switch from either operative to its neutral position before the obvious that ythe contact arml 40 of this switch will be mechanically inoperative upon movement of the switch lever 41, except when l the plug 19 is in place. `A yspring 5l secured to pin`43 and to lever 41 serves to bringthe lever back into alinement with' contact arm 40 when the lever is moved without the plug in place, and so insures the plug `holey 42 being in placeto receive the plug in whatever position the switch has been left.-

It will be noted that l vhave made a construction wherein a single plug serves to mechanically lock into operative connection ya series of two or more switches either `of edto one terminal of ammeter 47 through binding posts on plate 48 within the switchboard. The other terminal of the ammeter 47 is connected tobinding lpost 49 on the omnibus plate 50. The positive terminal of the storage battery is connected at binding post 51 to the inner conducting andpivoting plate 17, which is `at all times in electrical connection with contact arm 21 pivotally mounted thereupon. The positive terminal of the dynamo 45 is connected to plate 52, which has socketf53 to receive thev blade of knife switch754, which is mounted upon and in connection with contactplate uponethe right side of the base 16 and which switch 54 operated by handle 56 extending through an opening in the front cover 15. Plate 52 is also connected to plate 57 upon the leftof the base and below and a little'distance from the left end of the inner conducting plate 17. Inter-posed between this plate 57 andthe conducting plate .plug 19 can be withdrawn. It will also be 17 isa-plate 58 connectedto one terminal of the voltmeter l'59 and upon this plate 58 is a rocking switchv 60 adaptedto be rocked on its lower side into contact-'with plate 57, or on its `upper side intocontact with conducting pivoting plate 17. `This`switch is normally held out of Contact with either ofY its said contact-plates by springv 60a-but is 'manually operated by a handlef61 extending? through the front cover 15. Thev other "ter^- Y minal of the voltmeter is4 connected' to bindi" ing post 62 upon the omnibus plate 50.v Between binding post 63 and" 64 'on the side@ lights, contact plate 24, andbinding posts 63a and `Gli on omnibus plate "50 respectively, are interposed by suitable wiring the side lights (not shown). Between binding posts G5 and 66 on 'head lights contact plate 25 and `posts 65a and 66a on `the omnibus plate 50 are interposed the head lights (not shown). Between post 67 on the tail light contact plate'26 and post 67l on the omnibus plate is interposed the tail light (not shown).

Above kthe left end ot' conducting pivoting `plate 17 is a small .plate 68 capable of being brought into connection with plate 17 by means of a rocking switch G9 on plate (38 Vbut Vnormally held out of such Contact by spring 69a.

PlateS is connected to dash or pilot light 7 O, which in turn is connected to the einnibus plate 50 by post 71. Plate G8 is also connected to plate 72 located on the base 1G to the right of upper conducting pivoting plate Bel. rIhis plate 72 has sockets to receive knife switch 7 3 which iis secured to and in electrical connection with the plate 34. Knife switch 73 is operated by handle 7-1 eX- tending out through the front `cover 15 of the switchboard. Another plate 75 is located to the right of conducting plate 31 and connected to plate 311 by means of knife switch 7 G secured to plate 34 and controlled by handle 77 extending without the front cover 15. A tonneau light or other light may be interposed between plate 75 and post 75 on the omnibus plate.

Between post 7 8 on the inner conducting pivoting plate 17 `and post78 on the omnibus plate may be interposed a cigar lighter (not shown), to which it will be seen battery current will be supplied without the plug 19 being -in place,- and, ot' course, without regard to position of either switch lever. i

As will be seen in Fig. 1 the shape and arrangement of the lighting switch contact arm and contact plates 2e, 25 and 2G is such that when the contact arm is in uprightposition, contact will be made Ato all three of these plates thereby lighting `the side lights, head light and tail light. In this `position a slight projection from the rear of contact arm 21 conveniently formed by stamping a recess 21a into the front of the contact arm, rests in the depression between the right side of the L-shaped portion of plate 24 and the left side of plate 25. lVhen the'contact arm 21 is swung part way to the left, its contact with head lights contact plate 25 is lost, but is retained as to side lights plate 24V andtail lights plate 2G. lnithis position the rearward projection on contact arm 21 engages recess 24e in the L-shaped portion of plate 2st. Upon movingcontact arm 21 farther to the lett its connection with plates 24 and 2G is broken andthe projection 21` engages a depression 78L in an insulation jblolck 79 immediately to the left of and'of the same thickness as plate 221. This block keeps the contact arm on a line with the contact plate and allows the contact arm to be easily and surely swung back onto plate 211. The engagement of the rearward projection of contact arm 21 in the Vdiierent recesses mentioned at its different positions holds the contact arm securely in place against vibration of the machine and against any tendency to motion with the lever 23 when the plug is removed, but as the projection and recesses have slanting sides the arm 21 can be easily moved when operatively connected to the lever by plug 19. The engagement of the projection with these depressions also indicates to the operators hand when desired positions have been reached when moving lever 23.

To secure good contact pressure to all the plates engaged by contact arm 2l, I have contact plates 2L and 25 lie flat against the base 1G, but' contact arm 26 while secured to base 16 at its right end has its lett end raised thereabove so as to make contact with the outward surface of the contact arm 21 and thereby hold it securely,7 against the plates 2s and 25 back of the arm 21. A loop 2G@ in contact plate 26 tends to give it greater resiliency for this purpose.

As will be shown more particularly .in Fig. 2 the pivoted contact arm 40 extends only a short distance below contact plate and is then replaced by an extension contact arm 8O mechanically connected in alinement with arm 40 but electrically insulated there from by a strip 81 of suitable insulating material.

Spaced apart side by side on the base 16 and to the right of .the middle or neutral position of extension Contact arm S0 are contact plates 82 and 83, which are so connected as to be two terminals ot the `ignition circuit from the magneto S4. To the left of middle or neutral position of Contact arm 40 and below plate 57 there is located on the base 16 a contact plate S5 connected to one pole ot' the battery coil 86 of the battery ignition circuit.

Below contact plate S5 and to the lett of contact arm S0 when at its middle or neutral position are located upon the base 16 but spaced apart thereon two contact plates 87 and 88. Plate S7 is connected to omnibus plate 50 at post 87a. Plate 88 has mounted thereon by means of bracket 89 a spurred wheel 90 on shaft v91 revolving in plate S8 and bracket S9. and having its forward end extended out through the front cover 15 of the switchboard and there provided with a handle 92 suitable to rotate said spurred wheel by the hand of the operator. A spring tension Contact arm 93 projecting from a small plate 9st conveniently located upon the base 1G and connected to the other pole of the battery coil 86, normally makes contact with'the spurred wheel 90, but has `its-,contact suiiciently interrupted byrotaing contact arm 4() to make eiiective contact with-plates 55 to the right or 85 to the lett,

` and in getting extension contactarm 180 to make eliiective contact with plates 82 and 83 to the right or 87 and88 to the left by reason of the numberof contacts to be made at one time by such aswing switch, I form, as in dicatedparticularly in Fig. 1.5, all these contact plates of resilient material and shaped to curve outwardly at their central portion, which will be the part that will come under the contact arms, while their ends farthest from the contact `arms are secured to ystift'- plate 95 placed ,belowl said resilient plates. The ends of said resilient Vplates toward the contact arms slope back over the adjacent ends of the underlying plates 95 and extend loosely beneath an insulating mat 96, which is located in the space between the right and left series of these contact plates to enable the contact arms 40 and 80 to be freely moved onto either the right or left series of these plates, and also to hold said contact arms in neutral position by theV slight friction between said matk and said contact arms. It will now be seen thatV each of these resilient contact plates will spring outwardly enough to make its own contact with the contact arm moved thereover.l

Bearing in mind the mechanical and electrical constructions and connections hereinbefore detailed, it will be evident that the operation of the switchboard will be 'as follows: Assuming the engine to be stopped, the plug 19 mustl irst `be inserted to make the ignition and charging switch lever 41 operative, then that lever is swung Vfrom its middle or neutral position to the left whereupon the battery coil ignition circuit is closed by thetwo contacts so formed: the first, between plate 85, which is in direct connection with the battery coil, and the swinging contact arm 40 which is in connection with the upper pivoting and conducting plate 84 and thereby in connection successively with plug 19, lower pivoting plate 17 and positive terminal of the storage battery the second, between plates 88 and 87 by means of theextension contact arm 80, as theplate 88 is connected through the in'- terrupting wheel 90 to the other terminal of the battery'coil, while plate87 is connected through omnibus plate 50 to the negative pole of thestorage battery. The two contacts so made'operate as the closure of a double pole switch to complete the ignition circuit from the battery coil. In a nonvibrating coil the necessary interruption of the current is obtained by the operator ro- -battery from tating spurred wheel 90, and the ammeter 47-v indicates iI" current is flowing through the battery coil. The voltage ofthe storagebat-V tery may now be tested by raising the handle G1 of the rocking switch 60 whereby one sider of this switch is brought into .contact with the inner pivoting plate 17 Upon the engine and the dynamo 45 being started, the ignition and charging switch lever 41 is swun over toits riht hand 30- sition to makefthe ignition circuit from the magneto 84 complete by the connection made between the two terminals-thereof, viz: contact plates 82 and l83 by means of extension contact arm' 80. y.The same movement of this switch lever has also moved contact arm 40 onto plate 55 and assuming switch 54 to be closed,'the dynamo will at once beput in' connection with and begin to charge the storage battery 45, connection being madefrom switch 54 to plate 52 and thence direct to the positive `terminal of the dynamo; while from plate' 55 connection is made through contact arm 40, upper pivoting plate 34, plug 19, lower contact plate 17,

which is connected to the positive pole of the storage battery 46. The-voltage may now be indicated by pressing down the handle 61 of rocking switch 60, which then makes contact with plate 57, which is'in connection with plate 52, which in turn is'in direct connection with the positive terminal of the dynamo 45. When desired the charging of the storage battery 46 may be discontinued by opening switch 54, which has noeect on the magneto circuit while leaving contact Aarm 40 still in contact with' plate 55. The battery may then 4befurther charged by closing switch 54.

The magnetocircuit is broken by moving lever 41 and therewith contact arm 80-to the middle or neutral position, which movement of lever 41valso breaks the contact between plate 55 and contact arm 40 and thereby breaks the circuit between the storage battery and the dynamo, which prevents the discharging through the dynamo. n

With the locking device formed by the D-shaped hole inlever 41, the plug 19 cannot be removed unless the lever 41 is brought to its neutral position and, therefore, the operator in order to remove the plug must bring the lever 41 to such position that the circuit from the storage battery through 4the dynamo is also broken.

A modified form of my invention is to construct the dynamo contact plate 55 which is in connection with one terminal of the dynamo, of such shape that it will make contact with contact arm 40 both when that arm is swung to the right as heretofore described and as shown particularly in F ig. 1, and also when said contact arm- 40 is swung to the left but not when the contact arm is in its middle position. Such a modiiied form of plate is shown in Fig. 14 in which tothe original shape oi' the plate is added a contact plate 55L to the left of middle positionA of contact arm 4.0 and an arm 55b electrically connecting said plate 55 and its left hand portion 55, but so arranged toward the top that the contact arm will not touch said arm 55b when the contact arm is at neutral position. XWith this modified form of contact plate 55, it will be seen that when the arm 1-O is moved to its right hand position the magneto ignition circuit will be operative and the dynamo will beconnected tocharge the battery as already described; that when the Contact arm is moved to its left` hand posi-tion the ignition circuit from the storage battery will be closed as'before shownand also that the dynamo willbe con.- nected through plate 55a to charge the storage battery while at the neutral position of the contact arm when neither ignition cir.- cuit; is closed, the connection between the dynamo and storage battery will also, be broken thus preventing the storage battery fromv discharging into the dynamo when the engine isnot running. By swinging arm 21 to` right of perpendicular it engages recess, 25e in plate 25 andmaliescontact onlywith side.v light plate 25 andy tail light plate 26 thereby lighting only the. side lightsl and tail*l light.

That I claim as new and desire to secure by Letters` Patent is:

l, In. an electrical switch, a pivoting conducting plate, a contact,y plate spaced therefrom, a contact arm pivoted to said pivoting` plate, and adaptedto `be swung intoc011- `tact with said contact plate, a switch lever pivotally connected to said contact armand removable means connecting said switch lever and Contact arm at a point other than their said pivotal connection whereby said arinis locked to movement with said lever only when said removable, connection is in place.

2. In-an electrical switch apivoting conducting plate, a contact plate spaced there.- from, a Contact arm pivotedto said pivotal plate and adapted to be swung into, contact with, said. contact plate, a switch lever pivotally connected to said contact arm ata point other than its connection with said pivoting plate andfremovable means connecting-.said switch lever andcontact arm at a pointe()-I inciding with the axis ofthe pivotal .connectionwbetween said pivotal platey andl said arm whereby said arm is lockedto movement with said lever only when said removable connection is in place.

3., In an electrical switch, a conducting plate having a plug hole therein, a flange onsaid rplate surrounding said plug hole, a Contact: plate spaced from `said conducting plete, a; Contact; arm pivotally vemulated f 01.1.

said flange and adapted. tov be swung into contact with said Contact plate, aswitch lever pivotally connected to saidv contact arm at a point other than its pivotaI connection with said conducting plate and having a pluo hole adapted to be brought into line with the plug hole in said conducting plate, and a removable plug adapted to be inserted in said plug holes when in alinement and lock said contact arm to movement with said lever.

a. In an electrical switch, a conducting plate having a plug holetherein, a flangeon said plate surrounding saidv plug hole, a contact plate spaced from saidconducting plate, a contact arm pivotally mounted on said flange and adapted; to be swung into contact` with said contact plate, a switch` lever. pivotally connected to said contact arm4 at a point other than its pivotal connection withsaid conducting-plate, and al plug hole adapted to. be brought into` line withL the plug hole in said conducting. plate, aA removable plug adapted to beinserted in said plugholes wheninalinement and lock said contact arm to movement withsaidzlever and means preventing the removal ofysaid plug except. when said lever and contact arm` are in a, predetermined i position.

5. In an electrical switchboard-a plurality of superimposed conducting, plates, a plurality of contactplates spaced therefrom, a Contact arm pivoted'. to each ot saidconductingplates withtheir axes in alinement and adapted to be swung into contact;` with their respective contact plates, aiswitch lever pivotally. connected to cachot saidl contact arms at a point other than at its connection with said pivotal plate and a single removable plug oi?I conductive materiall inserted throughr all.. said; switch levers andf contact arms at a point coinciding with theaxis of the pivotal connection between said pivotal plates and said arms whereby said arms. are locked: to movementwith their, respective, levers and said conducting plates are electrically .connected only when 4said removaljile. plug isin place.

6.A In an electrical switchapivotinggconductingplate, a contact plate. spacedrthererv from, a contact army pivoted tofsaid pivotal plate and adapted to be swung into contact' with said contact plate, a. switch: lever pivotally connected-tosaidcontact armat a point other thanitsconnectionwith said pivoting plate andafremovable. plug1 adapted 'to bey inserted through said `switcl-r .lever andicontactV arm at; a point, coinciding Awith thev aXis of the pivotalconnection.between said pivotal plate andsaid: arm whereby said arm is locked f to lnoveinentwith said leverA only. when said plugis. in place and means .preventing the yremoval ofzsaidfplug except when ysaid lever, and contact;arm Iare in.` a predetermined position.

7. In an electrical switch board, a plu# s rality of superimposed pivoting conducting plates, a plurality of contact platesspaced therefrom, a contact arm pivoted to each of said pivotal plates with their axes in aline- .ment and adapted to be'swunginto contact with their respective'contact plates, a switch lever pivotally connected to each of said contact arms at point other than itsv con@ nection with its said pivoting plate, a single removable plug inserted through alll said.

switch levers and contact armsat a point coinciding with the axis of the pivotal co-n- Ynection between. said contact plates and said ,y

arms wherebysaid arms are locked to movey ment with their respective levers only when said plug is in'place and means adapted to prevent the `removal of said plug eXcept when one of said levers and its arm are in a predeterminedv position.

` 8. In an electrical switch board `a plurality of superimposed, individually insulated conducting. plates, a plurality of co-ntact plates spacedtherefrom, a contact arm pivotedl to each of said conducting platesv with their axes in alinement andadaptedto be swung intocontact with their respective contact plates, a switch lever pivotally connected to each of said contact arms at a point other` than at its connection with said pivotal plate, a single removable plug of 'conductive` material inserted through all said switchlevers and contact arms at a; point coinciding with the axis of ythe p1v levers and its arm are in a predetermined position.

9. In an electrical switch, a contact plate, a contact arm adapted tobe swung into oontact with said contact plate, a switch lever pivotally connected to said contact arm and removable means connecting said switch lever and contact arm at a point other than their said pivotal connection whereby said arm-islocked to movement with said lever place.

to said pivoting plate and adapted to lbe swung into contact with said contact-plate,

Va switch lever pivotally connected to saidl contact arm at a point other than its connection with said pivoting plate and removable means connecting said switch lever and contact arm `at a 'point other than their Vsaid rpivotal connection whereby said arm is locked* to movement with said lever only when said removable connection is in place.v

11. In an electrical switch a pivot, a contact plate, a Contact arm pivoted to said Aonly when said removable connection is in 1 In an electrical switch, a 'pivoting plate, a contact plate, va contact arm pivoted pivot and adapted tol be swung into contact" with said contact plate, a switch lever pivotally connected to said contact arm at a point other than its connection with said pivot and removable means connecting said switch lever and contactA arm at a point coinciding with the axis of the pivoting connection between said pivotl and said arm whereby said arm is locked to movement with said lever only when said removable connection is in place. Y i

i12. In an electrical switch board,'a plurality of superimposed pivoting plates, a

plurality of contact plates, a contact arm f pivot'ed to each of said pivotal plates with their axes in alinement and adapted tobe swung into contact with their respective contact plates, a switch lever pivotally connected to each of said` contact arms at a point other than its connection with its said pivoting plate and a single removable plug inserted through all said switch levers and contact arms at a point coinciding with theA axis ot the pivotal connection between said contact plates and said arms whereby said arms are locked to movement with their ref spective levers only when said plug is inV place. Y

In witness whereof I have affixed my signature, in the presence of two witnesses, this 19th day of December 1911.

MONTGOMERY. H. JOHNSON. IVitnesses: f HARR'IET WILLIAMS, n JAMES H. MERWIN.

' Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

` Washington, D. C. 

